If the overdrive control switch is in the normal ON position, the clutch will engage after the shift to fourth gear, and above approximately 45 mph. If the control switch is in the OFF position, the clutch will engage after the shift to third gear, at approximately 35 mph at light throttle.

you should feel it unlock as you coast down from cruise. mine runs 2k at 65

If the overdrive control switch is in the normal ON position, the clutch will engage after the shift to fourth gear, and above approximately 45 mph. If the control switch is in the OFF position, the clutch will engage after the shift to third gear, at approximately 35 mph at light throttle.

you should feel it unlock as you coast down from cruise. mine runs 2k at 65

Like everyone said... You can also keep your foot on the gas (when your above 50mph) and slightly touch your brake pedal it should kick right out and unlock and youll see rpm rise.. If not then your torque convertor isn't working...

Our 4.0 locks at like 50mph, the 5.9 locks at around 35-40mph depending how light im tapping the pedal

I'm pretty sure my OD is working, cause if I turn it off my rpms jump up, and if I turn it back on they drop.

But, if I tap the brake pedal at 65mph, the rpms do not jump up. And, I do not get another drop in RPM after 4th gear (OD).

So, it sounds like my TCL is not working.

Any ideas as to the cause.

FWIW, I just bought the Jeep with 158K on the Odometer, but was told by the seller that he just had an engine put in with only 104K on it. So, could it be something that was done wrong with the engine swap?

FWIW, I just bought the Jeep with 158K on the Odometer, but was told by the seller that he just had an engine put in with only 104K on it. So, could it be something that was done wrong with the engine swap?